The present disclosure relates to a semiconductor device and its manufacture. More particularly, the present disclosure relates to a semiconductor device including wafer-level light emitting diode and a method for manufacturing the semiconductor device including a light emitting diode at the wafer-level.
A light emitting diode (LED) is a semiconductor device that transforms electrical power into a light source. The semiconductor device has a p-type region and an n-type region separated by a junction. The p-type region is dominated by positive electric charges, and the n-type region is dominated by negative electric charges. The junction acts as a barrier to the flow of electrons between the p-type and the n-type regions. Only when sufficient voltage is applied to the semiconductor device, can the current flow, and the electrons cross the junction from the n-type region into the p-type region. Once an electron enters the p-type region, it will recombine with a positive charge and emit a photon of light. The characteristics of this light, such as its color, depend on the design and materials used in the semiconductor device, and many different designs and materials are well known.
Compared with other light sources, the LED has advantages of low input voltage, low power consumption, and quick response time. Further, the LED can be mass produced and are light weight. The LED is ubiquitous in many areas of modern life, including electronic, communication, automotive, and consumer product fields.
As the market trend is moving towards thin and small electronic products, such as in the mobile phone market, LED manufacturers are also forced to keep improving their designs to provide for a smaller LED. Conventional LED manufacturing techniques include die bond and wire bond, molding, plating, and some require trimming and forming processes. Extensive manufacturing steps increase the expense of making an LED. Further, the current manufacturing steps produce an LED that is both wide and thick, and the overall volume of the LED is much greater than the ideal compared to the area of the LED actually producing light.
A convention LED structure requires a current source, which is provided from a semiconductor structure positioned along a side of a light emitting diode. The light emitting diode includes a p-type portion near the top, an n-type portion near the bottom, and emits light from the top. Current flows into the light emitting structure and is provided to the p-type region with a wire attached through soldering to the top of light emitting diode to contact the p-type portion of the light emitting structure. Current leaves the light emitting through a substrate underneath the light emitting structure. This results in an LED that is significantly wider and thicker than the light emitting diode.